Generator of accurately timed pulses



March 13, 1951 R. F. FOSTER 2,545,349

GENERATOR 0F ACCURATELY TIMED PULSES Filed Dec. 17, 1947 INPUT Inventor: Raymond F. Foster,

His Attorney.

Patented Mar. 13, 1951 RaymomhlkEostemstratfordiconne assi nmrtn; Generah Electric; Qomn nn: an momtiom at? New lurk- ApplicationD'eceinber fl, 1947: serialiNmaszgr-m 1;. Tl'iisainvecntiomrelates'torsignahgeneratingssyse temsmndit-he-zlike andYmoreparticularlSniO sucihaa, system-wherein a; singlez'accurately 'timed": signalz. is developed in response to mcontroiisignali lttiszamobjecticofithis:invention torpmvifleten. impmvedz signal-12 generating circuit; whereim: the: andzlampfitudez off-the: generated psignaii issindenendent; off charactemsticsscfithez com- It'zisaa: fiimtheltfibjhuh invention improv idea. sig aiigeneratihg-rcircuiit issinsensitiveathznoisesamlfothen extraneousirrbere feieinggsignaisithatimaw sbeereceivedawithithezcone tmifisignall;

furthen'objecizofi thissinventiomiszto: provide" amimproyeif of; 171181 ahovee-mentionexii type,- imw-hichithe; generated: signal is: initiated inure? sgonsessolelwtm aacontrolzsignailof predetermined: oharacteristicsr Yet another object ofithiszinventiom isto: pro? wide; improvedi'means" in: szuchu a: circuit whereby thesgenemtedi signali issdeiayed': at predetenmined; timewith: respect: tmthe: initiating: s-ignaili.

a: fiirtherfohjectz of, this: inventionris: to: pmidesinzwcirouitrof theraboyes-mentionedity. e; means-Ito: accomplish: the: above; enumeratedi odor- 1 jectsby meansroi; argasseous; discharge? in;-- corporated' in-grthe' signal}. generating? circuit; and withoutit-lierneectofiadditional "electronzdischarges d'eyiceszand: associated-,componentszi 4 1clalimsa, (Cl. ,250;+-27

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are applied-rte? fifi 100111701 eleetrodeaz i'ofi eieotrorr. dischargeid'evice 32': Thezbiaszomcontrolielectrhde:

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charging circuit-of capacitor: I6: comprisesfisouree' gointzofidevicm I 1; isasomewhatlesst than:the-,-.time

41. the: inhuttterminalseofi the: present: cirouiIfi-rindi- I r) to I herresponsivew solely to; signalsaofi a: predetene I mined;- duration; and: shorter s-ignalsesvemthou hi of; greaterimagnitudmsuch as thosemmducedby? noism havesno, efiect 3011*. the voperationiofzthe cire cuite The; manner in: which: these; features: are refilizethwillinomheedescribedz, I

imam/ale duringzwhichl devicezt is; maintained. nonconductive by, thSiGOIItIDl :sighafli ltiiise apparent; that, un'lessrg'ai Sig-nah is"; received omterminai's; I; whiehilastsemoreatharr atpredeterg minedatimer; interval;., not potential is; developed across; resistom lib as; device;- IZL has-mot ,beenremderedconduotive; Thereforeemtimeadei'ay iSjQfJ fectiveiy introduced:betweenathmoccurrence?of; a signal atrterminais Ir: andLthe-appearance of asigie naliaerossaresistoryI18f;mid:undesiredatransientisignals: lasting: less: tham thiss. predeterminedi mini:- mumitimegintermlihaxeanoi effectwmthemgemrtion of the pulse generating circuit, now to be described.

Device I9 is normally nonconductive, the control electrode 20 being biased beyond the cutoff point of this device by the unidirectional biasing source 2!. 'The-negative terminal of biasing source 2| is connected to control electrode 20 through resistor 22. Control electrode 20 is also coupled to device I! through a capacitor 23, as shown. The anode 24 of device I9 is directly connected to the unidirectional source 6, and cathode 25 of this device is connected to ground through the common cathode impedance ID. The output ofthe pulse generating circuit may be taken across impedance l asshown.

In the absence of a control signal the device 3 is conductive. Upon receipt of a control signal of predetermined amplitude and duration control electrode 2 of device 3 is suddenly driven negative beyond the cutofi' value of this device and conduction ceases. Capacitor l6 then commences to charge by means of energy received from source 5 through resistor 8. When the control signal has the correct characteristics,

device 3 remains nonconductive for an interval sufiicient for the charge on capacitor IE to build up a potential across this capacitor of such a value as to render device H conductive. A potential then appears across resistor it the characteristics of this potential being independent of the control pulse characteristics, and being dependent only upon the Values of resistors 8 and I8, capacitor l6 and potential source 6.

The potential appearing across resistor I8 is applied to the control electrode 2i) of device I9 through capacito 23 driving this control electrode positive and rendering device l9 suddenly conductive. The current through device i9 intended to cover all such modifications as fall within the true Scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. Asignal generating system adapted to be actuated by a control signal, comprising, 2. normally conductive electron discharge device and a second electron discharge device normally biased to a non-conductive state, each of said devices having an anode, a cathode and a control electrode, means responsive to said control signal for rendering said first-mentioned electron discharge device non-conductive for a predetermined time interval, means for rendering said second discharge device conductive at a predetermined point of said time interval, said last-mentioned means including a gaseous discharge device and capacitance means connected between the anode of said first-mentioned electron discharge device and the control electrode of said second electron discharge device, and. means for returning said electron discharge devices to their normal state after a further predetermined time interval;

2. A signal translating system comprising a normally conductive electron discharge device having an anode circuit and a normally non-concauses a rise in potential across cathode resistor the potential'on the control electrode 20 exceeds a certain value. This potential decreases at a predetermined rate as capacitor 23 charges through resistors i8, 22 andbiasing source 2i. As capacitor 23 charges, the control electrode 20 becomes less positive thereby reducing the current in device i9 and rendering the cathode 9 of device 3 similarly less positive. 7 At the end of a predetermined time interval, the positive potential on cathode 9 is sufiiciently reduced to allow the device 3 to, draw a small current through resistor 8. The consequent decrease in the potential of anode l is transferred through device ii and capacitor 23 to control electrode 20, which causes a further decrease in the current through the device id. The effect is cumulative, and the device 3 is quickly returned to its normal conductive state. When device 3 is in its normal state, the potential impressed upon device 57 is not suificient to exceed the discharge threshold of this device and this device also returns to its normal nonconductive state.

Output may be taken across impedance H3, and it can be seen that the potential developed across this impedance, in response to a control pulse of a predetermined duration, has a Wavetion has been shown, it is obvious that modifications may be made, and the appended claims are ductive electron discharge device having a control electrode circuit, signal control means for causing the anode potential of said first-mentioned device to increase for a predetermined time interval, means for rendering said second electrol discharge device conductive at a predetermined point of said time interval, said last-mem tioned means including a gaseous discharge device and capacitance means coupled between said anode circuit and said control electrode circuit, and means for returning said electron discharge devices to their normal state after a further predetermined time interval.

3. In a signal generating system, a first and a second electron discharge device each having a grid circuit and an anode circuit, a cathode load impedance common to all said circuits, biasing means for rendering said first device normally conductive and said second device normally nonconductive, a separate anode load impedance'in the anode circuit of said first device, means for impressing a control signal on the grid circuit of said first device so as to render said first device non-conductive for a predetermined time interval and thereby to increase the voltage on said anode load impedance, means for rendering said second device conductive at a predetermined point of time in said time interval, said lastmentioned means comprising a capacitance shunting the anode load impedance of said first device and a gaseous discharge device serially coupling said anode load impedance to the grid circuit of said second device, means responsive to the current in said common cathode impedance for returning said discharge devices to their nor mal states after a further predetermined time interval, and an output load circuit coupled to said common cathode impedance.

4. In combination, a first and a second electron discharge device, each of said devices having an anode, a cathode and a control electrode, common impedance means for coupling said cathodes to a point of reference potential, means for posi-' tively biasing the control electrode of said first discharge device to render this device normally conductive, means for negatively biasing the control electrode of said second discharge device to render this device normally non-conductive, control signal means for rendering'saidfirst device non-conductive for a predetermined time interval, means for rendering said second device conductive at a predetermined point of said time interval, said last-mentioned means comprising a capacitance coupling the anode of said first device 5 to a point of reference potential and a gaseous discharge device coupling said anode to the control electrode of said second discharge device, and means for returning said electron discharge devices to their normal state after a further pre- 10 determined time interval.

RAYMOND F. FOSTER.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,266,154 Blumlein Dec. 16, 1941 2,405,843 Moe Aug. 13, 1946 2,446,850 Root Aug. 10, 1948 

